The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Conventional staircases are constructed on-site through a reinforced concrete structure or a steel structure. Installation of on-site cast concrete staircases is a very difficult and time-consuming operation in traditional concrete skeleton structures. The process requires scaffolding, steel cutting, reinforcement and concrete molding and de-molding, which can cost as much as 8-10% of the building with its finishes.
Thus, many construction companies and builders have tried to improve the stair building process by using precast concrete staircases, to be quick and clean with the added benefit that the units can be used as soon as they are installed. However, a full flight of precast concrete stairs is heavy, requiring large cranes for transportation. Furthermore, the full flight of precast stairs may not be suitable for small projects and owner-builders.
Attempts in the prior art to improve the practicality of precast staircases include splitting the whole staircase into heavy components (see U.S. Pat. No. 4,248,020 to Zielinski, U.S. Pat. No. 4,995,205 to Bennett, U.S. Pat. No. 3,805,464 to Hanson and U.S. Pat. No. 5,491,939 to Wang—each incorporated by reference herein in its entirety).
Others have tried to minimize the weight of precast components by turning the stair flights into modular longitudinal units (see U.S. Pat. No. 7,469,516 to Smith—incorporated by reference herein in its entirety) which is nevertheless fraught with constructional complexities.
From the foregoing, it will be desirable to provide a staircase and a method of manufacturing thereof which is strong, safe, economical, of relatively light weight, facilitates a simple installation for unskilled labor and self-builders. Limitations and disadvantages of the prior art are overcome by the various disclosed embodiments of the present invention.